httpkadmind: Allow host SPNs to fetch selves
Combined with the synthetic_clients feature, this will allow hosts that have a PKINIT-worthy client certificate with a SAN with their host principals to create their own principals and "extract" their host keytabs. Together with some other PKIX credential bootstrapping protocol, this can help hosts bootstrap Kerberos host credentials.
This commit is contained in:
Nicolas Williams
@@ -160,6 +160,23 @@ but using
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.Nm [ext_keytab]
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as the
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.Nm krb5.conf(5) section.
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Clients with host-based principals for the the host service can
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create and extract keys for their own service name, but otherwise
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a number of service names are not denied:
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.Bl -tag -width Ds -offset indent
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.It Dq host
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.It Dq root
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.It Dq exceed
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.El
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as well as all the service names for Heimdal-specific services:
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.Bl -tag -width Ds -offset indent
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.It Dq krbtgt
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.It Dq iprop
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.It Dq kadmin
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.It Dq hprop
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.It Dq WELLKNOWN
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.It Dq K
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.El
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.Pp
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Supported options:
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.Bl -tag -width Ds -offset indent
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@@ -171,6 +171,7 @@ typedef struct kadmin_request_desc {
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unsigned int revoke:1;
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unsigned int create:1;
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unsigned int ro:1;
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unsigned int is_self:1;
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char frombuf[128];
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} *kadmin_request_desc;
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@@ -875,7 +876,7 @@ check_service_name(kadmin_request_desc r, const char *name)
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return 0;
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krb5_set_error_message(r->context, EACCES,
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"No one is allowed to fetch keys for "
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"Heimdal service %s because of authorizer "
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"service \"%s\" because of authorizer "
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"limitations", name);
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return EACCES;
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}
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@@ -916,6 +917,8 @@ param_cb(void *d,
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strcmp(key, "rotate") == 0 ||
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strcmp(key, "create") == 0 ||
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strcmp(key, "ro") == 0) {
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heim_audit_addkv((heim_svc_req_desc)r, KDC_AUDIT_VIS,
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"requested_option", "%s", key);
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if (!val || strcmp(val, "true") != 0)
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krb5_set_error_message(r->context, ret = EINVAL,
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"get-keys \"%s\" q-param accepts "
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@@ -930,19 +933,31 @@ param_cb(void *d,
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r->create = 1;
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else if (strcmp(key, "ro") == 0)
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r->ro = 1;
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if (ret == 0)
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heim_audit_addkv((heim_svc_req_desc)r, KDC_AUDIT_VIS,
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"requested_option", "%s", key);
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} else if (strcmp(key, "dNSName") == 0 && val) {
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heim_audit_addkv((heim_svc_req_desc)r, KDC_AUDIT_VIS,
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"requested_dNSName", "%s", val);
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if (r->is_self) {
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krb5_set_error_message(r->context, ret = EACCES,
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"only one service may be requested for self");
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} else if (strchr(val, '.') == NULL) {
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krb5_set_error_message(r->context, ret = EACCES,
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"dNSName must have at least one '.' in it");
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} else {
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s = heim_string_create(val);
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if (!s)
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ret = krb5_enomem(r->context);
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else
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ret = heim_array_append_value(r->hostnames, s);
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heim_audit_addkv((heim_svc_req_desc)r, KDC_AUDIT_VIS,
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"requested_dNSName", "%s", val);
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}
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if (ret == 0)
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ret = hx509_request_add_dns_name(r->context->hx509ctx, r->req, val);
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} else if (strcmp(key, "service") == 0 && val) {
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heim_audit_addkv((heim_svc_req_desc)r, KDC_AUDIT_VIS,
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"requested_service", "%s", val);
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if (r->is_self)
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krb5_set_error_message(r->context, ret = EACCES,
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"use \"spn\" for self");
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else
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ret = check_service_name(r, val);
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if (ret == 0) {
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s = heim_string_create(val);
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@@ -950,8 +965,6 @@ param_cb(void *d,
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ret = krb5_enomem(r->context);
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else
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ret = heim_array_append_value(r->service_names, s);
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heim_audit_addkv((heim_svc_req_desc)r, KDC_AUDIT_VIS,
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"requested_service", "%s", val);
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}
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} else if (strcmp(key, "enctypes") == 0 && val) {
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r->enctypes = strdup(val);
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@@ -959,6 +972,11 @@ param_cb(void *d,
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ret = krb5_enomem(r->context);
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heim_audit_addkv((heim_svc_req_desc)r, KDC_AUDIT_VIS,
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"requested_enctypes", "%s", val);
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} else if (r->is_self && strcmp(key, "spn") == 0 && val) {
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heim_audit_addkv((heim_svc_req_desc)r, KDC_AUDIT_VIS,
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"requested_spn", "%s", val);
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krb5_set_error_message(r->context, ret = EACCES,
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"only one service may be requested for self");
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} else if (strcmp(key, "spn") == 0 && val) {
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krb5_principal p = NULL;
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const char *hostname = "";
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@@ -971,17 +989,44 @@ param_cb(void *d,
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if (ret == 0 && krb5_principal_get_realm(r->context, p) == NULL)
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ret = krb5_principal_set_realm(r->context, p,
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r->realm ? r->realm : realm);
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/*
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* The SPN has to have two components.
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*
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* TODO: Support more components? Support AD-style NetBIOS computer
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* account names?
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*/
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if (ret == 0 && krb5_principal_get_num_comp(r->context, p) != 2)
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ret = ENOTSUP;
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if (ret == 0)
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/*
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* Allow only certain service names. Except that when
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* the SPN == the requestor's principal name then allow the "host"
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* service name.
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*/
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if (ret == 0) {
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const char *service =
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krb5_principal_get_comp_string(r->context, p, 0);
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if (strcmp(service, "host") == 0 &&
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krb5_principal_compare(r->context, p, r->cprinc) &&
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!r->is_self &&
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heim_array_get_length(r->hostnames) == 0 &&
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heim_array_get_length(r->spns) == 0) {
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r->is_self = 1;
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} else
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ret = check_service_name(r, service);
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}
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if (ret == 0 && !krb5_principal_compare(r->context, p, r->cprinc))
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ret = check_service_name(r,
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krb5_principal_get_comp_string(r->context,
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p, 0));
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if (ret == 0)
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if (ret == 0) {
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hostname = krb5_principal_get_comp_string(r->context, p, 1);
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if (!hostname || !strchr(hostname, '.'))
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krb5_set_error_message(r->context, ret = ENOTSUP,
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"Only host-based service names supported");
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}
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if (ret == 0 && r->realm)
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ret = krb5_principal_set_realm(r->context, p, r->realm);
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else if (ret == 0 && realm)
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@@ -1016,19 +1061,25 @@ authorize_req(kadmin_request_desc r)
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{
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krb5_error_code ret;
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r->is_self = 0;
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ret = hx509_request_init(r->context->hx509ctx, &r->req);
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if (ret)
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return bad_enomem(r, ret);
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(void) MHD_get_connection_values(r->connection, MHD_GET_ARGUMENT_KIND,
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param_cb, r);
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ret = r->ret;
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if (ret == EACCES)
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return bad_403(r, ret, "Not authorized to requested principal(s)");
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if (ret)
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return bad_req(r, ret, MHD_HTTP_SERVICE_UNAVAILABLE,
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"Could not handle query parameters");
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if (r->is_self)
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ret = 0;
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else
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ret = kdc_authorize_csr(r->context, "ext_keytab", r->req, r->cprinc);
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if (ret == EACCES || ret == EINVAL || ret == ENOTSUP ||
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ret == KRB5KDC_ERR_POLICY)
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return bad_403(r, ret, "Not authorized to requested certificate");
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return bad_403(r, ret, "Not authorized to requested principal(s)");
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if (ret)
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return bad_req(r, ret, MHD_HTTP_SERVICE_UNAVAILABLE,
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"Error checking authorization");
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@@ -65,7 +65,8 @@ restport2=@restport2@
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server=datan.test.h5l.se
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otherserver=other.test.h5l.se
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cache="FILE:${objdir}/cache.krb5"
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admincache="FILE:${objdir}/cache2.krb5"
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cache2="FILE:${objdir}/cache2.krb5"
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admincache="FILE:${objdir}/cache3.krb5"
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keyfile="${hx509_data}/key.der"
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keyfile2="${hx509_data}/key2.der"
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kt=${objdir}/kt
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@@ -81,10 +82,14 @@ kadmind="${kadmind} --keytab=${keytab} --detach -p $admport"
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httpkadmind2="${httpkadmind} --reverse-proxied -T Negotiate -p $restport2"
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httpkadmind="${httpkadmind} --reverse-proxied -T Negotiate -p $restport1"
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kinit2="${kinit} -c $cache2 ${afs_no_afslog}"
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kinit="${kinit} -c $cache ${afs_no_afslog}"
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adminklist="${klist} --hidden -v -c $admincache"
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klist2="${klist} --hidden -v -c $cache2"
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klist="${klist} --hidden -v -c $cache"
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kgetcred2="${kgetcred} -c $cache2"
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kgetcred="${kgetcred} -c $cache"
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kdestroy2="${kdestroy} -c $cache2 ${afs_no_unlog}"
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kdestroy="${kdestroy} -c $cache ${afs_no_unlog}"
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kx509="${kx509} -c $cache"
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@@ -159,11 +164,11 @@ get_keytab_POST() {
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get_keytab "$q" -X POST --data-binary @/dev/null -f "$@" &&
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{ echo "POST succeeded w/o CSRF token!"; return 1; }
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get_keytab "$q" -X POST --data-binary @/dev/null -D response-headers "$@"
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grep ^X-CSRF-Token: response-headers >/dev/null ||
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{ echo "POST w/o CSRF token had response w/o CSRF token!"; return 1; }
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get_keytab "$q" -X POST --data-binary @/dev/null -f \
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grep ^X-CSRF-Token: response-headers >/dev/null || return 1
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get_keytab "$q" -X POST --data-binary @/dev/null -D response-headers \
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-H "$(sed -e 's/\r//' response-headers | grep ^X-CSRF-Token:)" "$@"
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return $?
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grep '^HTTP/1.1 200' response-headers >/dev/null || return $?
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return 0
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}
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get_keytab_POST_redir() {
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@@ -481,6 +486,38 @@ $kimpersonate --ticket-flags=initial --ccache=$admincache -k $keytab -t aes128-c
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$adminklist -t >/dev/null ||
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{ echo "failed to setup kimpersonate credentials"; exit 2; }
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echo "Making PKINIT certs for KDC"
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${hxtool} issue-certificate \
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--self-signed \
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--issue-ca \
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--ca-private-key=FILE:${keyfile} \
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--subject="CN=CA,DC=test,DC=h5l,DC=se" \
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--certificate="FILE:ca.crt" || exit 1
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${hxtool} request-create \
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--subject="CN=kdc,DC=test,DC=h5l,DC=se" \
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--key=FILE:${keyfile2} \
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req-kdc.der || exit 1
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${hxtool} issue-certificate \
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--ca-certificate=FILE:$objdir/ca.crt,${keyfile} \
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--type="pkinit-kdc" \
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--pk-init-principal="krbtgt/TEST.H5L.SE@TEST.H5L.SE" \
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--req="PKCS10:req-kdc.der" \
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--certificate="FILE:kdc.crt" || exit 1
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${hxtool} request-create \
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--subject="CN=bar,DC=test,DC=h5l,DC=se" \
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--key=FILE:${keyfile2} \
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req-pkinit.der ||
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{ echo "Failed to make CSR for PKINIT client cert"; exit 1; }
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${hxtool} issue-certificate \
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--ca-certificate=FILE:$objdir/ca.crt,${keyfile} \
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--type="pkinit-client" \
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--pk-init-principal="host/synthesized.${domain}@$R" \
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--req="PKCS10:req-pkinit.der" \
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--lifetime=7d \
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--certificate="FILE:pkinit-synthetic.crt" ||
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{ echo "Failed to make PKINIT client cert"; exit 1; }
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echo "Starting kdc needed for httpkadmind authentication to kadmind"
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${kdc} --detach --testing || { echo "kdc failed to start"; exit 1; }
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kdcpid=`getpid kdc`
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@@ -585,6 +622,50 @@ cmp extracted_keytab.rest1 extracted_keytab.rest2 > /dev/null &&
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test "$(grep $p extracted_keytab.rest2 | wc -l)" -eq 3 ||
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{ echo "Wrong number of new keys!"; exit 1; }
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echo "Checking that host services as clients can self-serve"
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hn=synthesized.${domain}
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p=host/$hn
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KRB5CCNAME=$admincache ${kadmin} get -s $p &&
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{ echo "Internal error -- $p exists too soon"; exit 1; }
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${kinit2} -C "FILE:${objdir}/pkinit-synthetic.crt,${keyfile2}" ${p}@${R} || \
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{ echo "Failed to kinit with PKINIT client cert"; exit 1; }
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${kgetcred2} HTTP/localhost@$R || echo WAT
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${klist2}
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rm -f extracted_keytab*
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KRB5CCNAME=$cache2 \
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get_keytab_POST "spn=$p&create=true" -s -o "${objdir}/extracted_keytab" ||
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{ echo "Failed to create and extract host keys for self"; exit 1; }
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${ktutil} -k "${objdir}/extracted_keytab" list ||
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{ echo "Failed to create and extract host keys for self (bogus keytab)"; exit 1; }
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KRB5CCNAME=$admincache ${kadmin} get -s $p ||
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{ echo "Failed to create and extract host keys for self"; exit 1; }
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echo "Checking that host services can't get other host service principals"
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hn=nonexistent.${domain}
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p=host/$hn
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KRB5CCNAME=$cache2 \
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get_keytab_POST "spn=$p&create=true" -s -o "${objdir}/extracted_keytab2" &&
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{ echo "Failed to fail to create and extract host keys for other!"; exit 1; }
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${ktutil} -k "${objdir}/extracted_keytab2" list || true
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KRB5CCNAME=$admincache ${kadmin} get -s $p &&
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{ echo "Failed to fail to create and extract host keys for other!"; exit 1; }
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echo "Checking that host services can't get keys for themselves and others"
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hn=synthesized.${domain}
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p=host/$hn
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p2=host/nonexistent.${domain}
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${kinit2} -C "FILE:${objdir}/pkinit-synthetic.crt,${keyfile2}" ${p}@${R} || \
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{ echo "Failed to kinit with PKINIT client cert"; exit 1; }
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${kgetcred2} HTTP/localhost@$R || echo WAT
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${klist2}
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rm -f extracted_keytab*
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KRB5CCNAME=$cache2 \
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get_keytab_POST "spn=$p&spn=$p2&create=true" -s -o "${objdir}/extracted_keytab" &&
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{ echo "Failed to fail to create and extract host keys for other!"; exit 1; }
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${ktutil} -k "${objdir}/extracted_keytab2" list || true
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KRB5CCNAME=$admincache ${kadmin} get -s $p2 &&
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{ echo "Failed to fail to create and extract host keys for other!"; exit 1; }
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grep 'Internal error' messages.log &&
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{ echo "Internal errors in log"; exit 1; }
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@@ -593,7 +674,10 @@ sh ${leaks_kill} kadmind $kadmindpid || ec=1
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sh ${leaks_kill} kadmind $kadmind2pid || ec=1
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sh ${leaks_kill} kdc $kdcpid || ec=1
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trap "" EXIT
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if [ $ec = 0 ]; then
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trap "" EXIT
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echo "Success"
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fi
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# TODO
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#
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@@ -7,8 +7,8 @@
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name_canon_rules = as-is:realm=TEST.H5L.SE
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[appdefaults]
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pkinit_anchors = FILE:@objdir@/pkinit-anchor.pem
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pkinit_pool = FILE:@objdir@/pkinit-anchor.pem
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pkinit_anchors = FILE:@objdir@/ca.crt
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pkinit_pool = FILE:@objdir@/ca.crt
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[realms]
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TEST.H5L.SE = {
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@@ -19,9 +19,10 @@
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[kdc]
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num-kdc-processes = 1
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strict-nametypes = true
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synthetic_clients = true
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enable-pkinit = true
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pkinit_identity = PEM-FILE:@objdir@/user-issuer.pem
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pkinit_anchors = PEM-FILE:@objdir@/pkinit-anchor.pem
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pkinit_identity = FILE:@objdir@/kdc.crt,@srcdir@/../../lib/hx509/data/key2.der
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pkinit_anchors = FILE:@objdir@/ca.crt
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pkinit_mappings_file = @srcdir@/pki-mapping
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# Locate kdc plugins for testing
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@@ -30,11 +31,6 @@
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# Configure kdc plugins for testing
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simple_csr_authorizer_directory = @objdir@/simple_csr_authz
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enable-pkinit = true
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pkinit_identity = PEM-FILE:@objdir@/user-issuer.pem
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pkinit_anchors = PEM-FILE:@objdir@/pkinit-anchor.pem
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pkinit_mappings_file = @srcdir@/pki-mapping
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database = {
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dbname = @objdir@/current-db
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realm = TEST.H5L.SE
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